Abstract: A process for polymerizing vinyl halide monomer in a large capacity reactor. Liquid polymerization medium comprising water, surfactant, and monomer is charged to the reactor, polymerization catalyst is added, and the polymerization medium is agitated in a manner to provide substantially laminar flow along a circular path about a generally vertical centrally located axis in the reaction zone. The polymerization medium is agitated in a manner to provide localized turbulent mixing near the periphery of the reaction zone, and the polymerization medium is maintained within selected ranges of temperature and pressure through the action of a vertical condensing tube positioned at the top of the reactor.